1. Field of the Invention
The present invention relates to a recording apparatus and a recording method which perform recording by applying ink to a record medium, and more particularly, to the structure of an ink supply system and an ink supply method.
2. Related Background Art
In a recording apparatus of serial scan type, represented by an ink-jet recording apparatus, which performs recording by applying ink to a record medium, a so-called on-carriage tank system, a tube system, an on-demand system, an intermittent supply system or the like is adopted as a system of supplying the ink to a record head. The on-carriage tank system is the system that an ink tank is mounted on a carriage on which the record head is mounted, and the ink is supplied from the ink tank to the record head. The tube system is the system that an ink tank is disposed at the position distant from a carriage, the ink tank and the record head are connected to each other by a flexible tube or the like, and the ink is thus supplied through this tube. In the on-demand system, ink tanks are disposed both on a carriage and at the position distant from this carriage, and the ink is ordinarily supplied from the ink tank on the carriage to the record head. In this structure, only when an ink amount of the ink tank on the carriage lowers, both the ink tanks are connected to each other to supply the ink from the ink tank outside the carriage to the ink tank on the carriage.
In the on-carriage tank system, there is a case where a record-head-integrated ink tank integrally containing the record head and the ink tank is used. On the other hand, there is also a case where a head/tank separation/exchange ink tank in which only the ink tank is exchangeable is used to prevent that the record head is disposed according to exchange of the ink tank and to reduce running costs. In the on-carriage tank system as above, it is demanded to lower exchange frequency of the ink tank so as to reduce the running costs and decrease a load of user""s operation, whereby it is necessary to enlarge the capacity of the ink tank. However, if the capacity of the ink tank mounted on the carriage is enlarged, the weight of the entire carriage increases proportionally, whereby it becomes necessary to enlarge the apparatus as a whole and also reinforce the carriage driving unit and the carriage supporting unit.
Moreover, in the tube system, the tube brings a load to the movement of the carriage. Particularly, in recent years, the tube of which the ink supply amount per unit time is larger is required, and the weight of the tube in the ink supply state tends to increase, whereby the load to the carriage by the tube increases more and more. Moreover, since inertia force due to the movement of the carriage is applied to the ink inside the tube, an ink supply pressure varies, and there is a fear that unevenness in recording occurs.
In order to cope with such problems in the on-carriage tank system and the tube system, the intermittent supply system in which an ink tank (on-carriage ink tank) on a carriage and a main ink tank at the position distant from the carriage are connected to each other as needed to appropriately supply the ink to the on-carriage ink tank is proposed. In the intermittent supply system, the capacity of the on-carriage ink tank to which the ink is appropriately supplied can be small, and, ordinarily a user can supply the ink by exchanging the main ink tank. Here, since the main ink tank is disposed outside the carriage, the load to the carriage does not increase even if the capacity of this tank is enlarged, Thus, by enlarging the capacity of the main ink tank, it is possible to lower the exchange frequency of the ink tank and thus decrease the load of the user""s operation and the running costs.
As to the method of supplying the ink from the main ink tank to the on-carriage ink tank according to the intermittent supply system, the sequence to cause the apparatus to perform the ink supply is disclosed in U.S. Pat. No. 5,980,030. In this sequence, if the Ink of the on-carriage ink tank becomes equal to or lower than a predetermined level, the main ink tank and the on-carriage ink tank are connected to each other to supply the ink from the main ink tank to the on-carriage ink tank.
In the case where the sequence disclosed in U.S. Pat. No. 5,980,030, when the ink of the on-carriage ink tank becomes equal to or lower than the predetermined level, for example, the supply operation is performed even while the recording of one page is being performed. Since a certain time is required to perform the supply operation, if the supply operation is performed even while the recording of one page is being performed, there frequently occurs an extreme difference between the penetration times of the ink applied to the record medium before and after the supply operation. For this reason, there is a fear that band-like recorded unevenness occurs on a recorded image.
As a method of solving such a problem, the method disclosed in Japanese Patent Application Laid-Open No. 7-32606 is known. In this method, record data of a next page is stored beforehand in a memory of a recording apparatus, and then an ink amount required to record the next page is calculated on the basis of the stored record data. Then, if the ink amount held in the on-carriage ink tank is less than the calculated ink amount required to record the next page, the ink is supplied prior to the recording of the next page. However, in the method disclosed in Japanese Patent Application Laid-Open No. 7-32606, it is judged after the image data of one page is completely received whether or not the ink supply operation should be performed, and the record operation starts thereafter, whereby there is a drawback that a time from the beginning of the transmission of the image data to the end of the recording is prolonged. Moreover, in this method, since it is required to once store the entire record data of one page, a memory having a large capacity is required.
Moreover, there is also proposed another method in which, on the basis of the ink amount (called a maximum-required ink amount) which is required to record, on a page to be recorded next time, a so-called solid image corresponding to the image to which the ink should be maximally applied, it is judged whether the ink amount held in the on-carriage ink tank is less than the maximum-required ink amount. If the judgement is affirmative, the ink supply operation is performed. However, in this method, there is a case where the ink supply operation is performed even if the ink sufficient to actually perform the recording remains, whereby waste of time increases in the record operation.
An object of the present invention is to provide, in a recording apparatus of intermittent supply system, a recording apparatus and a recording method which can supply ink from a main ink tank to an on-carriage ink tank at appropriate timing, without performing an ink supply operation during a record operation of one page and delaying a start of the record operation.
Another object of the present invention is to provide an ink-jet recording apparatus which performs recording by emitting ink from a record head to a record medium in accordance with record data, comprising a carriage, equipped with the record head, for performing reciprocation, a first ink tank mounted on the carriage, a second ink tank disposed at a position distant from the carriage, an ink supply means for supplying the ink from the second ink tank to the first ink tank, a remaining ink amount detection means for detecting a remaining ink amount in the first ink tank, a first calculation storage means for calculating and storing an ink amount required to record a part of the image data while the image data is being received, a second calculation storage means for calculating and storing a maximum ink amount required to store the image data except for the portion calculated by the first calculation storage means, and a control means for starting the record operation at a time when a sum total value of the ink amount stored in the first calculation storage means and the maximum ink amount stored in the second calculation storage means becomes lower than the ink amount detected by the remaining ink amount detection means.